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Question
A student is unable to see clearly the words written on the black board placed at a distance of approximately 3 m from him. Name the defect of vision the boy is suffering from. State the possible causes of this defect and explain the method of correcting it.
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Solution
The boy is suffering from nearsightedness i.e. Myopia. The possible causes for this defect are Elongation of the eyeball.
Excessive curvature of the eye lens
This defect can be corrected by placing a concave lens in front of the eye.
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RELATED QUESTIONS
In a Std. X class out of 40 students 10 students use spectacles, 2 students have positive power and 8 students have negative power of lenses in their spectacles.
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(1) What does the negative power indicate?
(2) What does the positive power indicate?
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(4) What defect of eyesight do most of the students suffer from?
(5) Give two possible reasons for the above defect.
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Nearsightedness, this defect can be corrected by using spectacles with concave lens.
